Self-propelled drilling head

Abstract

A self-propelled drilling head for drilling in soil by means of a multi-stage method comprises the drilling head having a housing and a drilling head tip arranged in the housing, and a spacer provided on the drilling head tip, by means of which the drilling head tip is in contact with the housing in order to change the multi-stage method to a method with a reduced number of stages.

The invention claimed is: 
     
       1. A self-propelled drilling head for drilling in soil by means of a multi-stage process, comprising:
 a housing; and 
 a drilling head tip, having an outwardly directed end for contacting the soil during drilling, arranged in the housing; 
 an adapter arranged on the drilling head tip forward of the housing with respect to forward movement of the drilling head; 
 a removable spacer arranged between the housing and the adapter and configured for installation on the drilling head tip to place the drilling head tip in contact with the housing in order to change the multi-stage process to a process with a reduced number of stages; 
 wherein the adapter is removable for insertion and removal of the spacer. 
 
     
     
       2. The drilling head according to  claim 1 , wherein the spacer abuts against a front area of the housing. 
     
     
       3. The drilling head according to  claim 1 , wherein the drilling head tip is prestressed by means of the spacer. 
     
     
       4. The drilling head according to  claim 1 , wherein the spacer comprises an elastic plastic. 
     
     
       5. The drilling head according to  claim 1 , wherein the spacer is arranged in a ring around the drilling head tip. 
     
     
       6. The drilling head according to  claim 1 , wherein the spacer is formed of a plurality of parts. 
     
     
       7. In a self-propelled drilling head designed for underground drilling in soil according to a multi-stage process, the drilling head having a housing and a drilling head tip arranged in the housing, a method comprising:
 using a spacer in the self-propelled drilling head on the drilling head tip during underground drilling in soil, by means of which the drilling head tip is in contact with the housing in order to use the drilling head in an underground drilling method with a reduced number of stages, wherein, in one of the reduced number of stages, a percussion piston strikes both the drilling head tip and the housing. 
 
     
     
       8. A method for retrofitting a self-propelled drilling head for drilling underground in soil according to a multi-stage process, the drilling head having a housing and a drilling head tip arranged in the housing, comprising opening the housing and inserting a spacer, closing the housing to cause the spacer to come in contact with the drilling head tip and the housing in order to modify the multi-stage process of underground drilling by reducing the number of stages, wherein, in one of the reduced number of stages, a percussion piston strikes both the drilling head tip and the housing.